A lifeline represents an individual participant in the interaction.
To create a lifeline, simply double-click anywhere on the diagram canvas. For additional methods, refer to the Diagram Editor page.
Lifeline - UML Communication Diagram

Create a Lifeline from Component

From version 9.2 onwards in Astah Professional and Astah UML, lifelines can be created by dragging and dropping a component from the structure tree onto the diagram. This will create a Lifeline with the Component as its base class. This intuitive method simplifies the process of representing your system components as participants in the interaction.

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Links between Lifelines

To establish a connection between two lifelines, hover your mouse over a lifeline until the [L] icon appears, then click it to draw a link to another lifeline. This visual link represents the interaction path between the participants.
Create a Link in Communication Diagram

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Messages represent the communication between lifelines.
To create a message, ensure that the two lifelines are already connected with a link.

Create from the Tool Palette

  1. Select the [Message] tool from the palette.
  2. Click on the link connecting two lifelines to place a message. A red arrow appears indicating the direction of the message. Adjust the direction by moving your mouse and release to finalize the message’s direction.

Create Message from palette

Create via Suggest Feature

  1. Hover over a link connecting two lifelines to reveal the [S] button.
  2. Click the [S] button to automatically generate a message between the lifelines.Create a message in Communication Diagram